A stepper motor is a rotary motion apparatus which provides desired incremental angular rotation of a load in response to sequential input control pulses and will provide the desired angular movement of that load coupled with the motor in response to each pulse until the required load torque exceeds the electromagnetic capability of the motor.
A typical stepper motor as presently available in the open market is made and sold by Superior Electric Company of Bristol, Conn. as their Model M112FJ12. To provide a control apparatus, which can include a programmed microprocessor, operative to sequentially energize the stepper motor stator coils with the required control pulses to obtain a given angular speed, including accelerating and decelerating below the torque limits of the stepper motor, is well known in the prior art.
It is known in the prior art to provide a motor for opening and closing the passenger doors on a transit vehicle in response to door command signals from a vehicle automatic train operation control apparatus, as described in an article entitled Recent Applications of Microprocessor Technology to People Mover Systems by M. P. McDonald et al. and published in the proceedings for the 29th IEEE Vehicle Technology Group Conference held in Chicago, Ill. during March, 1979.